Safety-arming device

ABSTRACT

1. In a switch actuating means, the combination comprising an acceleration sensitive weight displaced in proportion to an accelerating force applied to said acceleration sensitive weight, a flywheel drivingly coupled to said acceleration sensitive weight and being driven in response to motion of said acceleration weight, a normally open switch having a movable contact bearing member, gear means coupling said contact bearing member to said flywheel and being actuated to close said switch by the momentum of said flywheel after the acceleration force is no longer applied to said weight.

United States Patent [1 1 Hoelzen June 12, 1973 SAFETY-ARMING DEVICE [75] Inventor: Warren R. Hoelzen, Ontario, Calif.

[73] Assignee: The United States of America as represented by the Secretary of the Navy, Washington, DC.

221 Filed: Sept. 29, 1960 21 Appl. No.: 59,454

2,993,492 7/1961 Vining 102/70.2

Primary ExaminerBenjamin A. Borchelt Assistant ExaminerThomas l-l. Webb Attorney-Joseph M. St. Amand, T. M. Phillips and W. O. Quesenberry EXEMPLARY CLAIM 1. In a switch actuating means, the combination comprising an acceleration sensitive weight displaced in proportion to an accelerating force applied to said acceleration sensitive weight, a flywheel drivingly coupled to said acceleration sensitive weight and being driven in response to motion of said acceleration weight, a normally open switch having a movable contact bearing member, gear means coupling said contact bearing member to said flywheel and being actuated to close said switch by the momentum of said flywheel after the acceleration force is no longer applied to said weight.

4 Claims, 2 Drawing Figures PAIENTED Jun 1 2 ms SHEETI 0F 2 ATTORNEYS PATENTED J11?" 2 I975 3. 738 .273

SHEET 2 [IF 2 WARREN R. HOE N INVENT ATTORNEYS SAFETY-ARMING DEVICE The invention herein described may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

The present invention relates to missile safety-arming devices and more particularly to safety-arming devices which arms only when a safe displacement is attained from its missile launching device.

A safety-arming device for guided missile application has two major functions in providing a positive control on the path of initiation of the warhead. First the device must assure with a high degree of certainty that no stray signal or impulse can cause initiation of the warhead during storage, handling, transportation or launching of the missile; and second,- after a predetermined safe separation interval from the launching site the device must reliably arm, aligning the explosive train and or completing any necessary electrical connections, making the warhead receptive to a firing signal.

Where arming distances fall within the boost phase of the missile rocket motor, arming requirements are currently being satisfactorily provided by safety-arming devices which utilize unbiased run-a-way escapements as a distance measuring device. Arming requirements which fall into the past boost phase of the missile flight being met by combination run-a-way escapement and mechanical timing devices which provide arming at a fixed period of time from the time of launch. The acceleration characteristics of missile boosters vary directly with environmental temperature. Fixed time devices result in a wide dispersion of arming distances which limits the tactical use of the missile system.

An object of the present invention is the provision of a novel safety-arming device which overcomes the disadvantages of other known devices.

Another object is to provide a safety-arming device which is reliable to arm a warhead at a safe distance.

A further object of the invention is the provision of a safety-arming device which will not arm if there is a burnout before reaching a safe distance from launcher.

Another object is the provision of a safety-arming device which provides improved safety by requiring forward motion of the missile throughout the arming cy cle.

Still another object is to provide a novel safetyarming device to provide fixed distance arming of missile warheads whether this distance falls within or after the missile boost phase.

Other objects and many of the attendant advantages of this invention will become readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:

FIG. 1 is a schematic diagram of the invention embodied in a relatively low acceleration device.

FIG. 2 is a schematic diagram of the invention embodied in a high acceleration device.

Referring now to the drawings, wherein like reference characters designate like or corresponding parts through the several views, there is shown in FIG. 1 a flywheel or rotating inertia disc 10 geared to a driving weight 11 by a gear train consisting of gears 12 and 13. Flywheel 10 is also geared to a geneva indexing mechanism 14 through gear 16. Brake element 17 and launch latch 18 are coupled to actuating member 19 by members 21 and 22 respectively. The safety and arming device is carried in a missile 25 which is launched in the direction indicated by arrow 30.

In operation, simultaneously with the launching of the missile solenoid 23 is energized causing brake element 17 to move to free flywheel l0 and latch 18 to move to free g-weight 24. The acceleration of the missile causes g-weight 24 to move down and to the left thereby compressing spring 27. The motion to the left is caused by slots 28, 29 and pins 31, 32. Integrating weight 11 is then permitted to move down to drive flywheel 10. The g-weight 24 prevents continued motion of the integrating weight 11 unless at least a minimum normal missile boost phase has occurred. Motion of g-weight 24 under acceleration is toward the rear and to the side, arrow 26, freeing integrating weight 11 to start acceleration aft against retardation of flywheel .10. Torque on flywheel l0 varies directly with missile acceleration, and the angular displacement of flywheel 10 will be directly related to acceleration, velocity and displacement of the missile. Should the boost impulse be of a duration that would be less than that to a normal boost, g-weight 24 will recapture integrating weight 11 and return it to the unarmed position. If, however, integrating weight 11 travels the distance corresponding to the minimum normal missile boost distance, g-weight 24 will clear integrating weight 11 upon returning at the end of boost and allow it to proceed toward the armed position. Flywheel l0 drives, through gear train 16, geneva indexing mechanism 14. When pin 33 engages slot 34, contact bearing member 36 moves to engage movable contact 37 with fixed contact 38 and movable contact 39 with fixed contact 41 to complete the arming circuit (not shown). Because of cam 42 and curved surfaces 43 and 44 switch bearing member 36 will be locked in either the closed or open position until pin 33 engages slot 34.

The device of FIG. 2 functions in the same manner asthe device of FIG. 1, but integrating weight 11 has been replaced with a pair of eccentrically weighted, counter-rotating rotors 51, 52.

In the devices of both FIGS. 1 and 2, after the end of boost, the energy stored in flywheel 10 will continue to drive weight 11 or rotors 51, 52. Missile drag accelerations reflected on weight 11 or rotors 51, 52 will reduce flywheel 10 turning rate to maintain proportionality to missile velocity and the position of weight 11 or rotors 51, 52 will continue to accurately be displaced in proportion to missile displacement.

Obviously many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed is:

1. In a switch actuating means, the combination comprising an acceleration sensitive weight displaced in proportion to an accelerating force applied to said acceleration sensitive weight, a flywheel drivingly coupled to said acceleration sensitive weight and being driven in response to motion of said acceleration weight, a normally open switch having a movable contact bearing member, gear means coupling said contact bearing member to said flywheel and being actuated to close said switch by the momentum of said flywheel after the acceleration force is no longer applied to said weight.

motion of said acceleration weight, a normally open switch having a contact bearing member, gear means coupling said contact bearing member to said flywheel and being actuated to said switch by the momentum of said flywheel after the acceleration force is no longer applied to said weight, and means coupled to said acceleration sensitive weight for returning it to its initial position if said flywheel fails to rotate a predetermined number of revolutions corresponding to a safe travel displacement of said missile warhead. 

1. In a switch actuating means, the combination comprising an acceleration sensitive weight displaced in proportion to an accelerating force applied to said acceleration sensitive weight, a flywheel drivingly coupled to said acceleration sensitive weight and being driven in response to motion of said acceleration weight, a normally open switch having a movable contact bearing member, gear means coupling said contact bearing member to said flywheel and being actuated to close said switch by the momentum of said flywheel after the acceleration force is no longer applied to said weight.
 2. The combination of claim 1 wherein said acceleration sensitive weight is a weighted rack.
 3. The combination of claim 1 wherein said acceleration sensitive weight is a pair of eccentrically weighted, counter-rotating rotors.
 4. In a safety-arming device for use with a guided missile warhead, the combination comprising an acceleration sensitive weight displaced in proportion to acceleration forces applied to said acceleration sensitive weight, a flywheel drivingly coupled to said acceleration sensitive weight and being driven in response to motion of said acceleration weight, a normally open switch having a contact bearing member, gear means coupling said contact bearing member to said flywheel and being actuated to said switch by the momentum of said flywheel after the acceleration force is no longer applied to said weight, and means coupled to said acceleration sensitive weight for returning it to its initial position if said flywheel fails to rotate a predetermined number of revolutions corresponding to a safe travel displacement of said missile warhead. 